(1) Field of the Invention
The present invention relates to a method of producing hydrogenated fatty acids having excellent color and stability.
(2) Description of the Prior Art
Hydrogenated fatty acid can be obtained by splitting oil or fat into fatty acid and hydrogenating the fatty acid; or hydrogenating oil or fat into hardened oil or fat and splitting the hardened oil or fat. It is commonly known that when fatty acid, oil or fat is hydrogenated, the hydrogenated fatty acid, oil or fat is less in the coloration and in the smell than the original fatty acid, oil or fat. However, the hydrogenated fatty acid, oil and fat are easily colored or oxidized when they are heated or used in a chemical reaction, and even when the hydrogenated fatty acid is distilled, the distilled hydrogenated fatty acid is still insufficient in the stability.
The inventors have made various investigations in order to obtain hydrogenated fatty acid having excellent color and stability in the heating and chemical reaction, and found out that the above described object can be attained by hydrogenating fatty acid, oil or fat in the presence of a hydrogenation catalyst and a reducing metal, and distilling the crude hydrogenated fatty acid; or splitting the hydrogenated oil or fat into a crude hydrogenated fatty acid, and distilling the crude hydrogenated fatty acid.
The inventors have made further investigations and found out that, when the above described hydrogenation is carried out in the presence of a hydrogenation catalyst, a reducing metal and at least one of boric acid compound and heavy phenolic compound, the hydrogenated fatty acid has lighter color and improved stability.